The present invention relates generally to eyeglasses, and more particularly to a uniquely configured eyeglass shield that permits a wearer to adjust a frame thereof to provide a variety of vertical viewing angles for specific sporting applications. As discussed in greater detail below, embodiments of the present invention provide a sports-specific shield which can be selectively adjusted by the wearer in order to customize the configuration and fit of the eyeglass shield for beneficial use in specific activities, without requiring the use of tools. The resulting eyeglass shield can therefore be utilized in demanding sporting situations that require either a heads-up or heads-down posture of the wearer, such as competitive running, driving, skiing, or bicycle racing.
Eyeglasses, and sunglasses in particular, have long been designed with the general objective of blocking the sun or other sources of bright light from one's eyes. Over time, various features and advancements in this technology have been developed. The evolution of numerous designs of dual and unitary lens glasses initially differed essentially only in aesthetic features. However, eyeglass and lens designs have further developed in response to various optical considerations such as optical clarity, resolution, field of vision, refraction, and other such qualities. Typically, the optical qualities of the lens are best when the wearer's line of sight (LOS) extends in parallel to the optical center line (OCL) the lens.
Although these advancements in eyeglass technology have provided substantial benefits for eyeglass wearers participating in a broad range of activities, several sporting activities often require the wearer to assume body postures that displace the wearer's LOS particularly in the vertical plane from consistently being aligned with the OCL of particular lens. In addition, unique facial structures and geometries can result in different fits that similarly prevent different wearers from commonly enjoying the superior optical characterisitics of a given eyeglass.
Many sporting activities may be characterized as requiring the user to assume either a heads-up or a heads-down posture. In the heads-up posture, which is illustrated in accompanying FIG. 6A, a wearer's head is in a generally upright vertical position directly above the shoulders. Thus, the OCL of the eyeglass lenses and the wearer's LOS tend to be aligned parallel and point more or less straight ahead. Activities such as running, driving, and the like, tend to encourage a heads-up posture of the wearer.
In the heads-down posture, a wearer assumes a generally forward-leaning posture with the head extending forwardly of the torso, shown generally in FIG. 6B. In the heads-down posture, the head is tucked in an aerodynamic position with the OCL of the eyeglass lens typically being directed at the ground in front of the wearer; while the LOS is angularaly displaced upwardly with respect to the long. Thus, in order to optimize forward vision the wearer must lift their head upwardly from the racing posture, in order to bring their LOS into parallel with the OCL. The racing posture also brings the LOS high enough on conventional lenses that the upper frame can limit the field of view in the vertical plane. Activities such as bicycle racing and others commonly require the wearer to assume a heads-down posture for long periods of time.
Finally, unique facial geometries can prevent some wearers from enjoying superior optical characteristics of a given frame and lens system. A given pair of eyeglasses often fits differently on different wearers due to differences in facial structure. As a result, some wearer's straight-ahead LOS may not pass through the lens in parallel with the OCL. For example, an eyeglass that has been designed to fit a majority of wearers may nevertheless sit too high or too low on certain wearers depending on the structure and geometry of their nose and face. Therefore, the facial structure, as well as the particular activity in which the wearer is engaged, can cause the eyeglass have a particular fit on the wearer that prevents optimal vertical alignment of the OCL of the lens with the desired LOS of the wearer.